<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表格全选</title>
    <style>
        table{
            border: 1px solid;
            width: 500px;
            margin-left: 30%;
        }

        td,th{
            text-align: center;
            border: 1px solid;
        }
        div{
            margin-top: 10px;
            margin-left: 30%;
        }

        .out{
            background-color: white;
        }
        .over{
            background-color: pink;
        }
    </style>

    <script>
        /*
            分析：
                1.全选：
                    * 获取所有的checkbox
                    * 遍历cb，设置每一个cb的状态为选中  checked
       */
        window.onload = function (){
            //给全选按钮绑定单机事件
            document.getElementById("selectAll").onclick = function () {
                //获取所有checkbox
                var cbs = document.getElementsByName("cb");
                for (var i = 0; i < cbs.length; i++) {
                    cbs[i].checked = true;
                }
            }

            document.getElementById("unSelectAll").onclick = function (){
                var cbs = document.getElementsByName("cb");
                for (var i = 0; i < cbs.length; i++) {
                    cbs[i].checked = false;
                }
            }

            document.getElementById("unSelectAll").onclick = function (){
                var cbs = document.getElementsByName("cb");
                for (var i = 0; i < cbs.length; i++) {
                    cbs[i].checked = !cbs[i].checked;
                }
            }

            document.getElementById("firstCb").onclick = function (){
                var cbs = document.getElementsByName("cb");
                for (var i = 0; i < cbs.length; i++) {
                    //this为当前对象，将其他cb的状态与当前cb状态一样
                    cbs[i].checked = this.checked;
                }
            }
        }


    </script>
</head>
<body>
    <table>
        <caption>学生信息表</caption>
        <tr>
            <th><input type="checkbox" name="cb" id="firstCb"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>操作</th>
        </tr>

        <tr>
            <td><input type="checkbox"  name="cb" ></td>
            <td>1</td>
            <td>令狐冲</td>
            <td>男</td>
            <td><a href="javascript:void(0);">删除</a></td>
        </tr>

        <tr>
            <td><input type="checkbox"  name="cb" ></td>
            <td>2</td>
            <td>任我行</td>
            <td>男</td>
            <td><a href="javascript:void(0);">删除</a></td>
        </tr>

        <tr>
            <td><input type="checkbox"  name="cb" ></td>
            <td>3</td>
            <td>岳不群</td>
            <td>?</td>
            <td><a href="javascript:void(0);">删除</a></td>
        </tr>

    </table>
    <div>
        <input type="button" id="selectAll" value="全选">
        <input type="button" id="unSelectAll" value="全不选">
        <input type="button" id="selectRev" value="反选">
    </div>
</body>
</html>